In the past year we have made progress in the following areas: (1) Rat Pheochromocytoma. Tyrosine hydroxylase (TH) was purified and characterized. The purified enzyme was used for production of antibodies in rabbits. The TH antisera were utilized for mapping adrenergic neuronal systems. (2) The epinephrine (E) neuronal system was investigated. The effects of physical stress on brain E levels were measured. The interaction between E neuronal systems and NE neuronal systems was studied. (3) The binding characteristics of dopamine (DA) agonist and antagonists to striatal membrane sites were studied. Thermal exposure makes it possible to differentiate DNA receptors with high affinity for DA agonists from those with high affinity for DA antagonists. (4) The dopamine agonist potencies of ergolines were investigated. Pergolide was found to be a potent DA agonist with antiparkinsonian efficacy.